Center-point device for lathes, &amp;c.



J. KELL.

CENTER POINT DEVICE FOR LATHES, 6L0.

APPLICATION FILED JULY, I9I9.

Patented July 6, 1920.

INVENTOR Jack I;

7 BY ya all ATTORNEYS UNITED "STATES PATENT or'nce.

JACOB KELL, 0E NEWABK, NEW JERSEY.

CENTER- POINT DEVICE FOR LATHE-S, 8w.

Application filed July 17,

app'ertains to make and use the same, refer-.

ence being had to the accompanying drawings, and to characters of reference marked thereon, which form a part of this specification.

The present invention has reference, generally, to improvements in centering attach ments for lathes, milling machines and the like; and the invention relates, more particularly, to a live or rotatable anti-friction center-point device for use in connection with the back-head or tail stock of lathes, milling machines, etc.

The invention has for its principal object to provide a live center-point capable of rotation about its longitudinal axis, and mounted, to rotate in connection with annular ball-bearing devices and a thrust ball bearing device.

Another object of the present invention is to provide, in connection with a live centerpoint of the kind above mentioned, means for adjusting and taking up the wear upon the supporting ball-bearings.

Another object of the present invention is to provide a novel construction of means for receiving and distributing lubricant to the ball-bearings of the novel live centerpoint.

arrangements Other objects of the present invention, not at this time more particularly enumerated, will be clearly ainderstood from the followin detailed description of the same,

ith the various objects of the present invention in view the same consists, ,primarily, in the novel constructwn of live cen ter-point hereinafter set forth; and, further- Specification of Letters Patent. Patented July 6, 1920.

1919. Serial No. 311,624.

The invention is clearly illustrated in the accompanylng drawings, in which Figure 1 1s a vertical long1tud1nal crosssection through the novel construction of center-point made according to and embodying the principles of my present invention.

Fig. 2 is a forward end elevation of the same; Fig. 3 is a transverse section taken on line 33 in Fig. 1; Fig. 4 is a transverse section taken on line 4-4 in Fig. l; and Fig. 5 is a transverse section taken on line 55 in said Fig. 1.

Similar characters of reference are employed in all of the hereinabove described views, to indicate corresponding parts.

Referrlng now to said drawlngs, the refer-' ence character 1 indicates the complete center-point made according to and embodying the principles of my present invention, the same comprising a hollow casing or barrel 2 closed at its rearward end by an-end wall 3. Integrally connected with the closed rear end. of said casing or barrel 2, and in longitudinal axial alinement with the same, is a tapered butt or stem 4, adapted to be re ceived in the tail spindle of the back-head of a lathe or the like, to operatively mount the novel center-point in connection therewith. Said casing or barrel 2 is provided with a cylindrical chamber 5 extending in-.

wardly from its forward end, said chamber 5 terminating at its inner end in socket chamber 6 of reduced diameter. -Arranged within said socket chamber 6 is a thrust ball-bearing device comprising a rear centrally perforated race disk 7, which is stopped against the end wall 3 of said casing or barrel 2, a forward centrally perforated rotatable race disk 8, and intermediate said respective race disks are disposed a series of anti-friction balls 9, retained in properly mutually spaced relation on to another by meansof a suitable ball-cage retaining ring 10. The reference character 11 indicates a cylindrical center-point member,

- provided with a fofwardly directed conical point or nose 12. Said center-,point'membec is provided with a shank 13 of'reduced diameter, the inner end ofwhich is formed with a reduced extensionl inproviding a shoulder 15, said reduced extension. '14 terminating in a still further reduced extension ,16. 1 v .Said center-point, member is arranged cured upon said reduced extension 14 of the shank 13 so as to back against the shoulder 15, and as thus arranged will rotate with the center-point member. The reduced terminating extension 16 of the shank 13 projects through the ball-cage 10 and into the perforation of the rear race disk 7, being free to turn in the latterwhich remains stationary.

' Arranged within said chamber 5 of the casing or barrel 2, and in association with the shank 13 of said center-point memberare a pair of lateral ball-bearing devices, comprising a rearward lateral ball-bearing device and a forward lateral ball-bearing device. Said rearward lateral ball-bearing device comprises an inner race ring 17 fixed on said shank 13 to rotate therewith, an outer race ring 18 having an inwardly facing cone-bearing 19, and intermediate said respective race rings are disposed a series of anti-friction balls 20, retainedin properly mutually spaced relation one to the other by means of a suitable ballcage or retaining ring 21.. Said outer race ring 18 is fitted snugly within the walls of said chamber 5 so as to be free, however, for longitudinal adjusting movement within said chamber 5. Saidforward lateral ballbearing device comprises an inner race ring 22 fixed on said shank 13 to rotate therewith, an outer race rin 23 having an outwardly facing cone-bearing 24, and intermediate said respective race rings are disposed a series of anti-friction balls 25, retained in properly mutually spaced relation one to the other by meansof a suitable ball-cage or:retaining ring 26. Said outer race ring 23 is fitted snugly within the walls of said chamher 5 so as to be free, however, for longitugeinal adjusting movement within said cham- Arranged between said respective outer race rings 18 and 23 is a separator ring 27, having on-its outer circumference a lubricant channel or groove 28, leading from the bottom of which radially through the body of the ring, are openings 28. to communicate with the lubricant space 29 between the lateral bal1-bearing devices. The wall of said casing or barrel 2 is provided, at a point opposite said separator ring 27, with an opening 30, normally closed'by the screw threaded plug 31, which serves as a; point of introductlon of a suitable lubricant for distribution to said lateral-ball-bearings. In

' like manner the wall of said casing or barrel 2 is further provided, at a point opposite said thrust ball-bearing device, with an opening 32, normally closed by the screw threaded plug 33, which serves as a point of introduction of .a suitable lubricant for distribution to said thrust ball-bearing.

In order to close the forward end of said casing or barrel 2 against the escape of lubricant from the interior thereof and against the entrance of dirt or other foreign substances in contact with the ball-bearing devices, and to also serve as a means for adjusting the several ball-bearing devices to take up any wear of the same, I provide a cap-plate 34 provided with a centrally disposed opening 35 through which the forward end of said center-point member projects, said opening snugly fitting said center-point member, yet permitting the latter to turn freely therein. Said cap-plate is provided upon its inner side with a marginal annular shoulder 34 which projects inwardly so as to bear against the outer racering 23. The periphery of said cap-plate is provided with screw-threads 36 to screw into internal screw threads 37 with which the outer end of said casing or barrel 2 is provided, and said cap-plate is further provided in its outer face with spanner wrench sockets 37, whereby a spanner wrench may be o'peratively applied thereto for turning said cap-plate to engage the same with said casing or barrel 2, and to cause the sa'me to apply an adjusting take-up thrust upon said ball-bearing devices.

From the above description it will be apparent that the center-point member is mountedwithrelation to the casing or barrel 2 so as to be free to rotate about its longitudinal axis with a minimum ,of friction, when the sharpened point or nose 12 thereof is moved into proper engagement with the work mounted in the lathe or other machine with which the center-point device is used.-

The thrust bearing engaging the rear end of the center-point member, holds the same against rearward movement or displacementfrom the work, while still permitting, by-

reason of the ball-bearings, a substantially frictionless rotation of the rear end of the center-point member, while the concentric ball-bearings supporting the shank of said center-point member laterally assure not only a substantially frictionless rotation of the latter, but securely retain the same in true longitudinal alinement to the axis of rotation. When the work is rotated in the lathe or other machine, the center-point,

member being free to turn with the work, is

thus assured against being 'worn', scored or softened by burning, consequently the wearing qualities of the nose 12 are greatly en- 7 hanced, a true axial alinement of the centerpolnt with the work is assured, and in high speed operations less power is consumed.

One of the novel and important features of the construction of my live center-point device consists of the arrangement and mounting of the ball-bearing devices in such a manner that the wear thereof may be taken up by proper adjusting manipulation, so that all undue play in the bearing devices is corrected or eliminated to constantly assure the true axial alinement and rotation of the center-point member without wabbling or undesired lateral play. The pressure of the work against the center-point tends to thrust the latter inwardly. This thrust is resisted mainly by the rear thrust bearing, but is also increasingly exerted upon the outwardly facing cone-bearing 24 of the forward annular bearing as the thrust bearing wears. The rearward annular bearing does not receive said thrust, but serves only to maintain the true axial alinement and rotation of the centerpoint against lat-, eral play. Since the race rings 22 and 17 of the respective forward and rearward annular bearings are fixed relative to the centerpoint, it follows that the longitudinal thrust of the latter transmitted to the balls 25 of said forward annular bearing by said race ring 22 will tend to crowd said balls against the outwardly facing cone-bearing 24, tending to wear the latter, whereas such thrust transmitted to the balls 20 of the rearward annular bearing by said race ring 17 will tend to separate or loosen said balls relative to the inwardly facing cone-bearing 19, whereby undue play effecting the axial ali'nement and tending to permit slight wabbling of the centerpoint might occur. It will therefore be understood; that the thrust of the centerpoint, with accompanying wear of the rear thrust bearing tends to tightenthe forward annularbearing and loosen the rearward annular bearing, producing uneven wear of the same, so that they do not run in true balanced and fitted mutual relation. This condition may be corrected in the following manner :.-The cap-plate 34 is screwed inwardly a sufficient distance to cause the annular shoulder 34 to press slightly inward said outer racering 23, thus loosening the balls 25 to reduce the crowding effect and to bring the same back .to a normal smoothly adjusted running condition, and at the same time said inward movement of said race-ring 23 is transmitted, through the intermediate ring 27, to said'inner race-ring 18, tending to move the same toward the balls 20 to take up looseness and bring the same back to a normal smoothly running'condition, thereby balancing the ,running conditions of said respective annular bearings relative to each other, and also effecting the smooth easily running fit and relation of their respective parts, which is so necessary for themaintenance of the centerpoint in axially true rotation. proper regulation and adjustment of the said ball-bearing devices may be easily and quickly made, to assure the free yet true rotation of the center-point member, and, furthermore, said adjustments may be quickly and easily madewithout removal of the centerpoint device from the back-head of the lathe or other machine when desired. i

Another novel feature of the construction of my centerpoint device, lies in the means provided for introducing lubricant for distribution to the ball-bearings. The lateral ball-bearings receive the lubricant between It will thus be apparent that v the same, from the annular channel and openings provided in the separator ring 27 which permits the lubricant when introduced to enter the receiving space 29. The thrust ball-bearing receives the lubricant directly in contact with its balls, since the lubricant is directly introduced between the race disks 7 and 8.

I .am aware that some changes may be made in the several arrangements and combinations of the various devices and parts of my invention, as well as in the details of the construction of the same, without departing from the scope of the invention as above described, and as defined in the appended claims. Hence, I do not limit my invention tothe exact arrangements and combinations of the said parts as above described, nor do I confine myself to the exact details of the construction of said parts as. illustrated in the accompanying drawings.

' I claim r 1. In a device of the kind described, a rotatable center-point member, aholder having an inwardly extending chamber for the reception of the rearward portion of said center-point member, a thrust ball-bearing device seated in the rear'end of said chami bear against the forward outer race-ring to' impart an adjusting movement to the latter and through said separator'ring to the rearward outer race-ring, and said cap-plate having a central opening through which the forward end of said center-point member projects. I

2. In a device of the kind described, a rotatable center-point member, a holder having an inwardly extending chamber for the reception ofthe rearward portion of said center-point member, a thrust ball-bearing device seated-in the rear end of said chamher with which the inner end of said center- ;point member cooperates, a rearward inner I race-ring,

a forward inner race-ring, said inner race-rings being fixed on said centerpoint member in longitudinally spaced relation to 'each other, a rearward outer racering having a rearwardly facing internal ---outer race-ring, and said cap-plate having a central opening through which the forward end of said center-pointmember projects.

3. In a device of the kind described, a rotatable center-point member, a holder having an inwardly extendingchamber for the reception of the rearward portion of said center-point member, a thrust ball-bearing device seated in the rear end of said chamber with which the inner end of said centerpoint member-cooperates, a rearward inner race-ring, a forward inner race-ring, said inner race-rings being fixed on said centerpoint member in longitudinally spaced relation to each other, a rearward outer racering having a rearwardly facing internal cone-bearing portion, a forward outer racering having 'a forwardly facing internal cone-bearing portion, a separator ring interposed between said outer race-rings, said 4 outer raceerings being capable of longitudinal adjusting movement within said holder,

a series of anti-friction balls arranged to run between. said respective forward and rearward inner and outer race rings, a capplate threaded to screw into the outer open end of said holder, said ca -plate havin on its inner side an annular inwardly pro ecting shoulder to c said forward outer race-ring, said cap-piatehaving a central openi ng'through which the forward end of said center-point member projects, said separator ring'having in its outer circumference an annular channel provided at its .bottom with openings leading to the inner side of said separator ring, the walls of said holder having a lubricant entrancewopening opposite said separator-ring, and means normally closing said entrance opening. 4. In a device of the kind described, a rotatable center-point member a holder having an inward extending chamber forthe reception of the rearward portion of said center-point member, a thrust ball-bearing device in the'rear end of said chamher with which the inner end of said centerpomt member cooperates, a rearward inner race-ring, a forward inner race-ring, said ,.--race-rings bein fixed on said center-point member in longltudinally spaced relation to each other, a rearwardouter race-rlng'havscrew into the outer open end of said holder,

said cap-plate havingon its inner side an annular inwardly projecting shoulder to engage said forward outer race-ring, said capplate having 'a central opening through which the forward end of said center-point member projects, said separator ring having in its outer circumference an annular channel provided atits bottom with openings leading to the inner side of said separator ring, the walls of said holder having a lubricant entrance opening opposite said separator-ring, said walls of said holder having a second lubricant entrance opening opposite said thrust ball-bearing (device, and

means for closing said respective entrance openings.

5. In a device of the kind described, a rotatable center-point member, a holder having an inwardly extending chamber for the reception of the rearward portion of said center-point member, a rear race-disk seated .in the rear end of, said chamber, a forward race-disk fixed on the rear end of said centerpoint member to rotate therewith, a series of anti-friction balls between said race disks, a pair of longitudinally spaced inner racerings fixed on said center-point member, anti-friction balls riding on said inner race rings, a pair of outer race-rings against which said balls run, a separator ring between said outer race-rings, a cap-plate threaded to screw into the outer open end of said holder to bear against the forward outer race-ring to impart an adjusting movement to the latter and through said separator ring to the rearward outer race-ring, and said cap-plate having a central opening through which the forward end of said center-pointmember projects.

6. .In a device of the kind described, a rotatable center-point member, a holder having an inwardly extending chamber forthe reception of the rearward portion of said center-point member, a rear race-disk seated in the rear end of said chamber, a forward race-disk fixed on the rear end of said centerpoint member to rotate therewith, a series of anti-friction balls between said race disks,

a rearward inner race-ring, a forward inner race-ring, said nner race-rings belng fixed on said center polnt member in longitudi- -nally spaced relation to each other, a rearward outer race-ring having a rearwardly facing internal cone-bearing, a forward outer race-ring having a forwardly facing internal cone-bearing, a separator ring interposed between said outer race-rings, said outer race-rings being capable of longitudinal adjusting movement within said holder, a series of anti-friction balls arranged to run between said respective forward and rearward inner and outer race-rings, a capplate threaded to screw into the outer open end of saidholder, said cap-plate having on its inner side an annular inwardly projecting shoulder to engage said forward outer race-ring, and said cap-plate having a central opening through which the forward end of said center-point member projects.

7. In a deviceof the kind described, a rotatable center-point member, a holder having an inwardly extending chamber for thering interposed between said outer racerings, said outer race-rings being capable of longitudinal adjusting movementwithin said holder, a series of anti-friction balls arranged to run between said respective forward and rearward inner and outer race-rings, a cap-plate threaded to screw into the outer open end of said holder, said cap-plate having on its inner side an annular inwardly projecting shoulder t0 engage, said forward outer race-ring, said cap-plate having a central opening through which the forward end of said centerpoint member projects, said separator ring having on its outer circumference an annu-' lar channel provided at its bottom with openings leading to the inner side of said separator ring, the walls of said holder having a lubricant entrance opening opposite said separator ring, and means normally closing said entrance opening.

8. in a device of the kind described, a rotatable center-point member, a holder having an inwardly extending chamber for the reception of the rearward portion of said centerpoint member, a rear race-disk seated in the rear end of said chamber, a forward race-disk fixed on the rear end of said center-point member to rotate therewith, a series of anti-friction balls between said race disks, a rearward inner race-ring, a forward inner race-ring, said inner racerings being fixed on said center-point member in longitudinally spaced relation to each other, a rearward outer race-ring having a rearwardly facing internal cone-bearing, a

forward outer race-ring having a forwardly facing internal cone-bearing, a separator ring interposed between said outer racerings, said outer racerings being capable of longitudinal adjusting movement within said holder, aseries of anti-frictionballs arranged to run between said respective forward and rearward inner and outer racerings, a cap-plate threaded to screw into the outer open end of said holder, said cap-plate having on its inner side an annular inwardly projecting shoulder to engage said forward outer race-ring, said cap-plate having a central opening through which the forward end of said center-point member projects, sald separator ring having on its outer circumference an annular channel provided at its bottom with openings leading to the inner side of said separator ring, the walls of said holder having a lubricant entrance opening opposite said separator ring, said walls of said holder having a second lubricant entrance opening opposite the space 1nterme d1- ate said race-disks, and means for closing said respective entrance openings.

In testimony that I claim the invention set forth above I have hereunto set my hand this 17th day of June, 1919.

JACOB KELL.

Witnesses:

GEORGE D. RICHARDS, BARBARA SUTTERLIN. 

